BEGIN;
BEGIN
EXPLAIN (ANALYZE, BUFFERS)
select
	c_custkey,
	c_name,
	sum(l_extendedprice * (1 - l_discount)) as revenue,
	c_acctbal,
	n_name,
	c_address,
	c_phone,
	c_comment
from
	customer,
	orders,
	lineitem,
	nation
where
	c_custkey = o_custkey
	and l_orderkey = o_orderkey
	and o_orderdate >= date '1993-11-01'
	and o_orderdate < cast(date '1993-11-01' + interval '3 month' as date)
	and l_returnflag = 'R'
	and c_nationkey = n_nationkey
group by
	c_custkey,
	c_name,
	c_acctbal,
	c_phone,
	n_name,
	c_address,
	c_comment
order by
	revenue desc
LIMIT 20;
                                                                                                QUERY PLAN                                                                                                 
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Limit  (cost=1150485.06..1150485.11 rows=20 width=175) (actual time=32846.707..32846.716 rows=20 loops=1)
   Buffers: shared hit=834288 read=584619 written=9667
   ->  Sort  (cost=1150485.06..1151898.73 rows=565467 width=175) (actual time=32846.702..32846.705 rows=20 loops=1)
         Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount))))
         Sort Method: top-N heapsort  Memory: 30kB
         Buffers: shared hit=834288 read=584619 written=9667
         ->  HashAggregate  (cost=1129783.52..1135438.19 rows=565467 width=175) (actual time=32282.805..32680.798 rows=381515 loops=1)
               Group Key: customer.c_custkey, customer.c_name, customer.c_acctbal, customer.c_phone, nation.n_name, customer.c_address, customer.c_comment
               Buffers: shared hit=834285 read=584619 written=9667
               ->  Hash Join  (cost=351218.75..1115646.84 rows=565467 width=175) (actual time=4628.715..26762.434 rows=1148061 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=834285 read=584619 written=9667
                     ->  Hash Join  (cost=351217.19..1107870.11 rows=565467 width=153) (actual time=4628.680..26318.001 rows=1148061 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=834284 read=584619 written=9667
                           ->  Hash Join  (cost=282189.19..1030360.10 rows=565467 width=12) (actual time=2891.081..23489.176 rows=1148061 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=799006 read=584619 written=9667
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..686816.69 rows=14853329 width=12) (actual time=0.069..15341.440 rows=14823114 loops=1)
                                       Buffers: shared hit=606646 read=546372 written=9667
                                 ->  Hash  (cost=275022.09..275022.09 rows=573333 width=8) (actual time=2881.571..2881.571 rows=574039 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30616kB
                                       Buffers: shared hit=192360 read=38247
                                       ->  Bitmap Heap Scan on orders  (cost=12141.10..275022.09 rows=573333 width=8) (actual time=532.789..2596.638 rows=574039 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                             Heap Blocks: exact=229037
                                             Buffers: shared hit=192360 read=38247
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..11997.76 rows=573333 width=0) (actual time=391.342..391.342 rows=575753 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                                   Buffers: shared read=1570
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1726.174..1726.174 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=35278
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.019..815.467 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.018..0.018 rows=25 loops=1)
                           Buckets: 1024  Batches: 1  Memory Usage: 10kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.005..0.008 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.833 ms
 Execution time: 32887.941 ms
(42 rows)

COMMIT;
COMMIT